TEL AVIV, Israel — Prime Minister Benjamin Netanyahu rebuked a top Cabinet minister arriving in Washington on Sunday for talks with U.S. officials, according to an Israeli official, signaling widening cracks within the country’s leadership nearly five months into its war with Hamas.

The trip by Benny Gantz, a centrist political rival who joined Netanyahu’s wartime Cabinet following Hamas’ Oct. 7 attack, comes as friction between the U.S. and Netanyahu is rising over how to alleviate the suffering of Palestinians in Gaza and what the postwar plan for the enclave should look like.

An official from Netanyahu’s far-right Likud party said Gantz’s trip was planned without authorization from the Israeli leader. The official, who spoke on condition of anonymity, said Netanyahu had a “tough talk” with Gantz and told him the country has “just one prime minister.”

Gantz is scheduled to meet on Monday with U.S. Vice President Kamala Harris and national security adviser Jake Sullivan and on Tuesday with Secretary of State Antony Blinken, according to his National Unity Party. A second Israeli official speaking on condition of anonymity said Gantz’s visit is intended to strengthen ties with the U.S., bolster support for Israel’s war and push for the release of Israeli hostages.

In Egypt, talks were underway to broker a cease-fire before the Muslim holy month of Ramadan begins next week.

Israel did not send a delegation because it is waiting for answers from Hamas on two questions, according to a third Israeli government official who spoke on condition of anonymity. Israeli media reported that the government is waiting to learn which hostages are alive and how many Palestinian prisoners Hamas seeks in exchange for each.

All three Israeli officials spoke anonymously because they weren’t authorized to discuss the disputes with the media.

The U.S. began airdrops of aid into Gaza on Saturday, after dozens of Palestinians rushing to grab food from an Israel-organized convoy were killed last week. The airdrops circumvented an aid delivery system hobbled by Israeli restrictions, logistical issues and fighting in Gaza. Aid officials say airdrops are far less effective than deliveries by truck.

U.S. priorities in the region have increasingly been hampered by Netanyahu’s Cabinet, which is dominated by ultranationalists. Gantz’s more moderate party at times acts as a counterweight.

Netanyahu’s popularity has dropped since the war broke out, according to most opinion polls. Many Israelis hold him responsible for failing to stop the Oct. 7 cross-border raid by Hamas, which killed 1,200 people, mostly civilians, and took roughly 250 people as hostages into Gaza, including women, children and older adults, according to Israeli authorities.